Machine Gun Kelly Brings Beef With Eminem Onstage

Machine Gun Kelly thinks Eminem needs some target practice ... 'cause Em "missed" when he fired back at MGK in their escalating feud.

MGK mocked Eminem onstage Sunday night, wearing a shirt with the logo from Marshall's extremely homophobic diss track, "Killshot."

Kelly made sure the crowd at the Amway Center in Orlando knew exactly how he feels about Eminem, screaming "F**k Marshall Mathers" as he opened the set with his own song aimed at Em.

MGK takes a shot at Em's age (he's 45), yelling, "The real Slim Shady can't stand up."

Apparently, Orlando is siding with Kelly ... 'cause the crowd goes nuts.

Smart move by MGK's tour manager ... there's no stop scheduled for Detroit.

An actor named G-Rod did Em's bidding Friday night. He called MGK a "p***y" for his shot at Em's daughter. Two hours later, Kelly's crew beat the crap out of G-Rod.